Hetherington (Hethringham, Edrington), William (d. p. 1684), informer, was apparently from Ganderstown, Co. Louth. Little is known of his early life, but in 1667 he was employed to hunt tories in Laois and Offaly by Theophilus Jones (qv), and in Dublin by John King (qv), Lord Kingston. Imprisoned in Dundalk (1679) for debt and for dealings with tories, Hetherington met Edmund Murphy (qv), and persuaded him to swear to the existence of a catholic plot in Ireland. Escaping c. May 1679, he may have been present at the arrest of Oliver Plunkett (qv) in December 1679, but this seems unlikely. He eventually went to London, presenting himself to the earl of Shaftesbury (February 1680). The alleged ‘Irish plot’ proved useful to Shaftesbury's campaign to exclude James (qv), duke of York, from the succession; as a reward, Hetherington allegedly sought a colonel's commission to command a garrison in Ulster. He appeared before the privy council (24 March 1680), repeating Murphy's claims and seeking to implicate Plunkett and the viceroy James Butler (qv), duke of Ormond. His accusations were not unanimously accepted, and he was sent to Ireland to obtain further evidence. He returned to England (April 1680) with four witnesses, though they were later sent back to Ireland and Hetherington was dismissed.
Despite this, his association with Shaftesbury ensured that Hetherington would be the principal manager and procurer of the Irish witnesses eventually brought to England to bolster the claims of an Irish plot; in this role he also enjoyed the patronage of Henry Jones (qv), bishop of Meath. However, it remains uncertain to what extent Hetherington's activities stemmed from his own initiative, or were orchestrated by Shaftesbury; it was later claimed that Hetherington and Titus Oates suborned these witnesses, and Hetherington allegedly drafted Murphy's own testimony. He successfully petitioned (c. October 1680) for Plunkett's trial to be transferred to London from Ireland, and continued, along with Murphy and David Fitzgerald, to obtain witnesses. When testifying subsequently before the English house of commons, Hetherington denied any personal knowledge of a plot, ‘but did inform them of the miscarriages of the government’ (Ormond MSS, new ser., v, 486), with a particular emphasis on Ormond's alleged role in this. However, in November 1680 there were suggestions that Hetherington had manufactured evidence, and in December he was accused of withholding witnesses’ allowances. In January 1681 he became embroiled in a dispute with Fitzgerald, who claimed that Hetherington had pressurised witnesses, attempting to persuade them to swear against the queen, Ormond, and numerous others; these allegations against Hetherington were soon repeated by John MacMoyer (qv) and Hugh Duffy (qv). Hetherington vociferously denied them. In March Sir George Rawdon (qv) claimed to ‘have known Hetherington for a notable knave’ (CSPD 1680–81, 193); Ormond also made clear his distaste. These consistent accusations continued as the Irish witnesses gradually turned on him. Hetherington was imprisoned but bailed from Clerkenwell jail in May 1681. By now concerned about his future, he was subsequently imprisoned in Newgate for high treason. He remained loyal to Shaftesbury, though his fortunes would eventually decline with those of his patron.
Prior to his trial, Plunkett sought to discredit Hetherington, Murphy, and the other witnesses by revealing their criminal pasts. However, Hetherington was imprisoned during Plunkett's trial, and played no part in it, though the reasons for his detention remain obscure. In November 1681 he was arrested on a charge of scandalum magnatum brought by Ormond, and was ordered to pay £10,000 damages; his inability to pay saw him imprisoned again. In March 1682 he was accused of involvement in a plot to assassinate the king. He faced imminent prosecution in May 1683, but the details remain obscure. In February 1684 Hetherington was living in England, and was accused of trafficking in weapons. Nothing is known of him after this.